Re: [PATCH v4 3/3] config: allow overriding of global and system configuration

On Tue, Apr 13, 2021 at 03:33:08AM -0400, Jeff King wrote:

On Tue, Apr 13, 2021 at 09:11:52AM +0200, Patrick Steinhardt wrote:

quoted

+test_expect_success 'override global and system config with missing file' '
+	sane_unset GIT_CONFIG_NOSYSTEM &&
+	test_must_fail env GIT_CONFIG_GLOBAL=does-not-exist GIT_CONFIG_SYSTEM=/dev/null git config --global --list >actual &&
+	test_must_fail env GIT_CONFIG_GLOBAL=/dev/null GIT_CONFIG_SYSTEM=does-not-exist git config --system --list >actual &&
+	GIT_CONFIG_GLOBAL=does-not-exist GIT_CONFIG_SYSTEM=does-not-exist git version
+'

I was slightly surprised to see these still marked as test_must_fail.
But it's because git-config, when given a _specific_ file to read, will
complain if the file doesn't exist. And that is true independent of your
patch.

Yeah, surprising at first but then again it does feel sensible when
thinking about it: we ask git-config(1) to explitly list the
global/system-level configuration, and when it does not exist it does
feel sane to complain.

There is one interesting implication there. Running:

  GIT_CONFIG_SYSTEM=/dev/null git config --system --list

does _not_ complain, even though:

  GIT_CONFIG_NOSYSTEM=1 git config --system --list

does. IMHO that is quite sensible, but I wanted to point it out, as
using /dev/null is not an exact replacement for GIT_CONFIG_NOSYSTEM (in
my opinion it is even better ;) ).

Whereas this is the other edge case: we do ask it to explicitly list the
system-level configuration, and it _does_ exist even though it's empty.
I wouldn't expect to get an error here, and I do prefer this behaviour
to NOSYSTEM, too.

Patrick